Jumbo Frame Question

[heinz.kern]

I´m a bit confused regarding Jumbo frames on Cat6500.

when a jumbo frame enetrs the switch and

• has to go out an 100MBit-Interface with Jumbo disabled (MTU1500) -->it´s getting dropped by the switch ??
  
• has to go out an Gigabit-Interface with Jumbo disabled (MTU1500) -->it´s getting dropped by the switch ??
• has to go out an 100MBit-or Gigabit-Interface with Jumbo enabled (MTU9216) but no jumbo enabeld on the server-side-->it´s getting dropped by the server ??

thanks

[Sebastian Fernandez · Accepted solution]

Hello Friend, I hope  you find this link useful..

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.1E/native/configuration/guide/sw_int.html#wp1041111

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Note•Jumbo frame support fragments routed traffic in software on the MSFC.

•Jumbo frame support does not fragment bridged traffic.

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Basically if you dont have jumbo enabled, jumbo frames will be dropped if the traffic has to be bridged. If this is a routed traffic MSFC fragments the jumbo into small 1500 sized packets. If jumbo is enabled, it will forward the frame but other end not support will cerainly drop.

Also watch out for what modules in 6500 supports jumbo and read out for different scenario in the above document.

Please rate this post if you find it helpful.

Rgds,

Sebastian Fernandez